Wire take-up device for a drum filter



Feb. 26, 1957 R. c. WAHRMUND 2,782,935

WIRE TAKE-UP DEVICE FOR A DRUM FILTER Filed oct. 14, 1954 i' eels- WIRETAKE-UP DEVICE FOR A DRUM FILTER Robert C. Wahrmund, Baytown, Tex.,assigner, by mesne assignments, to Esso Research and EngineeringCompany, Elizabeth, N. J., a corporation of Delaware Application October14, 1954, Serial No. 462,329

4 Claims. (Cl. 210-199) This invention concerns a device for use withconventional types of rotary drum filters. The invention is specificallyconcerned with a device for maintaining tension on the wire which iswrapped around the cloth mounted on a rotary drum filter.

Drum type filters are employed at the present time in many applicationsand in connection with a variety of chemical processes. In general, arotary drum filter constitutes a large drum which is supported on anaxle so that the drum can be rotated. The cylindrical surface of thedrum is perforated and covered with a filter cloth. The drum ordinarilyis partially submerged in a tanlt containing a liquid mixture to befiltered so that suction may be applied through the drum to bring liquidinto the filter drum through the filter cloth as the drum is rotated.the drum is rotated, the filter cake formed on the drum may be exposedto a washing spray, a drying action, or other processing steps. Thefilter cake is removed from the drum during revolution of the filter bymeans of knives or so-called doctor blades.

In order to position the filter cloth on the drum and to firmly hold thefilter cloth in position, it is conventional to wind the drum with ahelix of line wire. Commonly two such wires are employed which encirclethe entire periphery of the drum at a spacing of a few inches.Commercial forms of such lters require wrapping wires which may be about200i) feet long. Because of the length of these wires substantialchanges in length may occur during filter operation. For one thing, theWire tends to wrap more tightly around the drum because of frictionbetween the wire and the knife blade used for removal of the wax cake.Again, during the long service life of a filter the wire is subject tocreep or Stretch. Because of these factors it is necessary to providemeans to take up excess wire during the useful life of a filter so as tomaintain suflicient tension on the wire at all times to hold the filtercloth firmly in position. In order to have a completely satisfactorytake-up device, it is desirable that the device be capable of taking upas much as feet of wire while still maintaining a strong tension on thewire. It is one of the objects of this invention to provide a specificform of wire take-up device which will provide this objective, namely,to automatically take up an extensive length of wire while maintainingadequate tension on the wire.

Provision of a suitable wire take-up device of the character identifiedalso entails necessity for letting out wire as well as taking up wire.This arises from the fact that rotary drum filters are commonly operatedat extremely low temperatures so that the wire can contract sufficientlyto set up breaking stresses. Consequently, it becomes necessary torelease wire from a take-up device whenever the filter is used atsubstantially lower temperatures than that of initial wire installation.Again it is one of the objects of this invention to provide a wiretake-up device which will automatically release In addition to thefiltering step indicated, as

nite States Patent sufficient wire to avoid breakage during lowtemperature operation.

The objects of this invention are achieved by provision of a novel wiretake-up device in which wire wrapped around the filter cloth of a drumfilter is wound on a sheave at one end of the filter. In order tocontrol take up or release of wire from this sheave, the sheave iscoupled to or fixed on a spindle which is normally maintained under atorsional bias by means of a torsional spring coupled to the spindle.This apparatus can be suitably designed by selection of the torsionalspring employed so that the sheave can take up ex` tensive lengths ofwire without serious change in the tension exerted on the wire.

The nature of this invention can be understood by reference to theaccompanying drawing which illustrates a preferred form of theinvention. In these drawings:

Fig. l illustrates in cross sectional detail the complete take-up deviceembodying the invention;

Fig. 2 is a left end view of the take-up device of Fig. l particularlyillustrating the manner in which wire is passed from the sheave of thedevice over the lter cloth of the filter; and, p

Fig. 3 is a sectional view showing how wire is wrapped around andfastened to the sheave.

In the drawings similar elements are identified by the same numerals soin the following description reference may be made to either and both ofthe figures of the drawing for a full understanding of the apparatus.The numeral 1 designates the end plate of a drum lter to which thetake-up device of this invention is mounted. The principal elements ofthe take-up device constitute a cylindrical spindle 2 having an axle 3on which a sheave 4 is mounted. These elements are mounted on the endplate 1 of the lter so that the spindle is positioned inside the drum ofthe filter while the sheave is outside of the iilter drum. A torsionalspring 5 extends along the length of the spindle and is positioned aboutthe spindle. As will be described, the torsional spring is coupled tothe spindle so that when the device is employed a torsional bias tendingto rotate the spindle will be maintained. In order to rotatably supportthe spindle and `in orderv to provide a protective housing about thespindle, a cover or housing is provided. As illustrated, the housing caninclude a length of pipe 6 which may be threaded at both ends. The leftend of pipe 6 may be threaded into a flange 7 which .can be bolted tothe end plate 1 of the filter by means of the bolts 8. The other end ofpipe 6 may be threaded into a similar flange 9 bolted to a blind ange orclosure member 10 by means of bolts 11. In order to rotatably supportthe spindle in the housing described, bearings are provided at eitherend of the spindle within the housing. As illustrated, it is convenientto employ spider bearings at both ends of the spindle designated bynumerals 12 and 13. These spider bearings essentially constitute a pairof concentric cylinders held together by spider arms providing an outerbearing surface intended to t tightly within the housing pipe 6 and aninner bearing surface adapted to support lthe 'axles of the spindle. Asillustrated, it is preferred to employ a carbon bushing 15 between theinner bearing surface of the bearings 12 and 13 and the axle of thespindle. In order to complete the Huid-tight housing of the spindle andspring, a plate 18 is located in the left end of pipe 6. The plate 18has arranged therein a sealing means 18a which bears on and seals aroundaxle 3. Conventional gaskets 19 and 20 may be provided adjacent theflanges of the housing in order to eliminate any possibility of liquidpassing into the housing.

In order to transmit torsional force from spring 5 to wegens the spindle2', spring 5 is fixed at one end to the spindle and at its other end tothe housing described. This can be simply achieved by passing anextensive end of spring 5 through a suitable perforation 22 provided byan extension'o'f the spindle 2 at its left end. The thei `e`n'cl ofspring 5 may have an extensive yportion 2 3 which is formed to extendinto one of the openingsfof the spider bearing 13. Rotation of spiderbearing 13 is prevented by rrieans of stop bar 24 which may be fixed orwelded to the bli nd flange 10. In this arrangement, the stop barprevents rotation of Vspider bearing 13 which in turn serves to fix end23of the torsional spring against rotation. It will'be understood thenthat by rotatingtlie spindle the spindle spring will be placed underatorsionalforge limited by; the spring characteristics and the,rnitieiisanplsuedliffiekirielflie dense` t The sheave 4 may be mountedon the extensive axle 3 Qf'spndle, A@by means 9i a holdieanutl threadedn @sendet axle. Wire smounfedtnn Sheaye by. wrapping .thQi'vire@bouillie Shrevev .running Queen@ .Qfi the Wire through hole 40 of thesheave and locking by means of set s crewsor `theldike. In order to control rotation of sheave 4, apawlZS is prrn/idedY which is 'positiene@to engage notched teeth 39 Provided .,611 the periphery of the sheave.Pawl 2,8 can be pivotally supported byva mounting screw 29 threaded intoend plate 1 of the filter. A spring 30 is mounted on screw 29 having oneend 'adapted to force the pawl 28 againstthe teeth of sheave 4. Theother4 end of spring 30 is held b y screw 31 so as to maintain the pawlspring under tension. N As particularly illustrated in Fig. 2, wireextending from, sheave 4 passes over a pulley, or spool 34 which ispositioned onthe yen d plated of the filter adjacent the periphery ofvthe drum of the lter. The Wire is thus guided from the sheave 4 overthe pulley to the surface ofthe drum. Y n

Inusing the apparatus described, when a filter is placed inservicethespindle is manually rotated, by means of a wrench` or thje like, inorder to establish the desired torsionalb'ias -of the spindle. Pawl 28is used to aid this coclging s tep. .The wrapping wire is then positioned about the LA clotl1`of the filter and brought over the pulleyto sheave 4.K Ihe end of the wire is fixed to the sheave anda number of.,turns of wire is provided on the'sheavc forletfout capacity, The pawlis then released and removedfrom the end plate, p lacing the full springtension qnthe wire. lInpractical applications, this `may be conducted soas to provide an initial tensionon the wire of about 25,0 pounds. Duringuse of the lter any extension ofmtherwire length will automaticallyYcause the wire ,tobeyrapped on sheave 4 under the torsional force-applied byspring 5. In the event the wire Vshortens -during Iuse, theincreased tension developed Willy-pull `additivonal rWire from thesheave against the torsional force Oflhe. Spring., Y Y Y Y apparent thatthe preferred device of this Vinventrondesribed is subject to manymodifications and ref inenrentsdwithin the concept yof `this invention.Forexallpinjyhile thelapparatus has been described as beingspppprvted-entuirely by one endplate of the filter, it is'apparenttlratother support provisions can be employed. In thisconnectiondthe takeaup device of this inventiomcan xed t9 wrein f or i ng ribs provided within the `filter Again ferraffeple .while rhetdevce1151's` been des ileduas including the particular housing illustrated,it is apparent'thatother types of housing could be vomplo" I nlthisconnection it is contemplated that f orh articular plicationsth'e devicecan be employed 1 ty fora protective housing. Particularly, itpossiblefto enivploy the take-up device described byfusing a'sing'l'evbearing 'at the'end'o'f the spindle adjacent the sheave and maintainingtorsional coupling between the spring and spindle by fixing one end ofthe spring with respect to the end plate of the filter and the other endof tlie spring to the spindle itself. These and other modifications ofthe invention are cmbraced within the scope of the following claims.

I claim:

l. A wire tensioning device for a continuous lfilter of the 'typeincluding a hollow, endplated filter drum, a filter cloth on theperiphery of said drumvand an emracing wire Wound around said cloth,said tensioning device comprising a spindle having an extensive axle,support meansconnectedwith said spindle and one of said end plates lforrotatably supporting said spindle on said end plate in the interior'ofsaid drum with said extensive axle of said spindle extending throughsaid end plate, a helical torsion spring about said spindle, meansinterconnecting said spring with said spindle and said support means, asheave fixed to said axle and carrying an end portion of said wire and apulley element on lsaid end plate 'of said drum adjacent the peripherythereof adapted to direct said wire from said sheave to the surfaceofsaid drum, whereby the torsional force of said spring may compensate forelongation and shortening of said wire.

2. The apparatus definedby claim 1 including a liquidtight housingpositioned about said spring and Ispindle provided with a liquid sealedpassage for said extension axle.

3. A wire tensioning device for a continuous filter of the typeincluding a hollow, end-plated filter drum, a filter cloth on theperiphery of said drum and an ernbracing wire wound around said cloth,said tensioning device comprising a spindle positioned within said drumand having an extensive and portion thereof extending through an end ofsaid drum, means to provide a torsional bias to said spindle, a sheavefixed to said extensive end of said spindle and carryingan end portionof said wire and a pulley `element adjacent the periphery of the filterdrum adapted to direct wire from said sheave to the surface of the drum,whereby the torsional bias of said spindle will cause compensation forelongation and shortening of said wire.

4. A wire ,tensioning device for a continuous filter of the typeincluding a hollow, end-plated filter drum, a filter cloth on theperiphery of said drum and an embracing wire wound around said cloth,said tensioning device comprising a spindle having an extensive axle, ahelical torsion spring about said spindle, a liquid-tight housing fixedto the interior of one of said end plates and containing said spindleand said spring, bearing elements for said spindle fitting within saidhousing to rotatably support'said spindle in said housing and toposition said spindle so that said extension axle extends through saidendplate of said filter drum, A'means for Yfixing one end of said springtosaid housing and means for fixing the other end Vofsaid spring to saidspindle, a sheave fixed to said'extensive axle and carrying a portion ofvsaid wire, and a pulley element on said end plate of said adjacent theperiphery thereof adapted to direct said wire from said sheave tothesurface of said drum, whereby the torsionalforce of said spring maycompensate 'for elongation and shortening of 'said wire.

nferattscnea mare *me of this parent UNITED STATES PATENTS

